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How long does it take to drill a gun barrel?

TDegenhart

TDegenhart

Diamond
Joined
Mar 26, 2011
Location
Geneva Illinois USA
Yes, I know, its like asking how long is a piece of string. Lets narrow it down to .30 dia, 30 inch long in high volume production. From a production standpoint, is this longest time element, rifling, or what?

Not a gunsmith or gun owner, just curious.

Tom
 
A book I have quotes drilling to .289" with a hss single point drill at 1 1/4 in per min feed.After drilling ,three reamings to bring the size to .300"A four groove barrel requires 100 passes per groove of a single tool cutter.This is WW2 production.Button rifling requires only one pass,as does hammerforging.Broaching requires one pass of a long broach,generally divided into three sections.The most modern applications of hammerforging dont need any drilling,tube swaged to dia ,then forged to all finished dimensions.probably 10 minutes,floor to floor.Explains the generous production of AKs.,one for every malcontent .Regards John.
 
1/2"/minute for 4140 steel spinning at 2650rpm with a single carbide gun drill. production speedsnfeeds are different refer Hoffmann, Webb, La Bounty info.

Cut rifling will take the longest time. Button rifling the shortest.
 
At the Shilen factory, their dual gun drill lathes take about 25 minutes for the drilling and their button rifling machine takes maybe 30 seconds. Been a couple years since I was there, but that's what I seem to remember.
 
Sounds like the way war production needs could be met could only be by banks of gun drills working 24/7, probably in many locations as well.

When reading about early musket making in the USA right after the revolution the numbers being produced always made me wonder, they had only high carbon steel tools to boot, and spindles running in bronze I suppose.

"Nearly 700,000 of these muskets were manufactured at Springfield Armory and Harpers Ferry over a 28 year period," NRA Museums:

Those are impressive numbers, and it sure would be fun to be able to go back in time and walk through Harpers Ferry Armory or Springfield Armory during this time, it's too bad we have to imagine it. Not only the manufacturing abilities but the resolve of our government at that time to do such a massive undertaking, such was the early commitment to holding on to what our forefathers had begun.
It's been said that only 15-20% of Americans actively expressed agreement with the need for a revolution as it was being fought, and yet only 15-40 years later defense was appreciated enough to support such efforts, and not only muskets but also pistols and more difficult, artillery.

parts
 
I make barrels do a living. 30 cal runs about an inch/min, maybe a bit quicker. Single reamer to bring it to size (.2997"). Then whichever rifling process the barrel is destined for.
 
partsproduction said:
Sounds like the way war production needs could be met could only be by banks of gun drills working 24/7, probably in many locations as well.

When reading about early musket making in the USA right after the revolution the numbers being produced always made me wonder, they had only high carbon steel tools to boot, and spindles running in bronze I suppose.

"Nearly 700,000 of these muskets were manufactured at Springfield Armory and Harpers Ferry over a 28 year period," NRA Museums:

Those are impressive numbers,
Click to expand...

They were able to make large numbers of muskets in that time by having huge factories full of people. There are photos available from the late 1800s of textile factories that filled entire valleys and 10s of thousands of people. Towns were built around the factory.

If you think about it, a modern computer controlled dedicated gun drilling machine that is 20 times faster than a manual process can be matched by 20 to 30 workers on manual machines. Back when labor was cheaper than machinery they could afford to have people hand filing threads on small screws all day every day.

Dan
 
What machines are used for drilling and rifling barrels?
Click to expand...
Not sure if you mean comercially or not. Some years ago plans were published for making a multi-purpose drilling, reaming and rifling machine all in one, a nice idea for someone producing just a few barrels per year. (http://lautard.com/rmv.htm)

Commercially it makes sense (To me, in my ignorance) to have a line, blanks go through one for drilling, then to the reaming station, then the next etc. Making large numbers like that they must do something like that, and in there too somewhere is straightening.
 
In World War II the biggest bottleneck to production was the rifling. At that time there was no hammer forging or button rifling, the grooves were cut one at a time in multiple passes. This led to the "two groove" 1903A3 rifle. The military tested the idea of rifle barrels with only two rifling grooves and found that the barrels performed well enough for military use. They then adopted the two groove barrels to be used on the 1903 rifles to cut down on production time.

If you get a chance to read Col. Julian Hatcher's "Hatcher's Notebook", he talks about barrel production and testing the two groove idea.
 
TDegenhart said:
Yes, I know, its like asking how long is a piece of string. Lets narrow it down to .30 dia, 30 inch long in high volume production. From a production standpoint, is this longest time element, rifling, or what?

Not a gunsmith or gun owner, just curious.

Tom
Click to expand...

Just an additional data point,...

FX airguns of Sweden brought out the "Smooth Twist" hammer forged barrels with only the few inches south of the muzzle rifled, in a move to increase production speed.

It so happens that most of the barrels shoot pretty straight. but..... that is sub sonic, with diabolo pellets.
 
A good discussion (with videos) of the different methods of rifling can be found on weaponsman.com (Who passed away last month)

Small- and Home-Shop Rifling Machines | WeaponsMan is perhaps the broadest discussion, with other good links being:

Rifling: A Gross History of a Technology | WeaponsMan (evolution of rifling)
How are Hammer Forged Barrels Made? And Why? | WeaponsMan (hammer forging)
Barrelmaking, a Century Past | WeaponsMan (a century of barrelmaking)
Small- and Home-Shop Rifling Machines | WeaponsMan (Home shop rifling)

Hope this helps
RB
 
It helped that such muskets were not rifled. Such as M1817 and M1842 - .69 caliber smooth bores

partsproduction said:
Sounds like the way war production needs could be met could only be by banks of gun drills working 24/7, probably in many locations as well.

When reading about early musket making in the USA right after the revolution the numbers being produced always made me wonder, they had only high carbon steel tools to boot, and spindles running in bronze I suppose.

"Nearly 700,000 of these muskets were manufactured at Springfield Armory and Harpers Ferry over a 28 year period," NRA Museums:

Those are impressive numbers, and it sure would be fun to be able to go back in time and walk through Harpers Ferry Armory or Springfield Armory during this time, it's too bad we have to imagine it. Not only the manufacturing abilities but the resolve of our government at that time to do such a massive undertaking, such was the early commitment to holding on to what our forefathers had begun.
It's been said that only 15-20% of Americans actively expressed agreement with the need for a revolution as it was being fought, and yet only 15-40 years later defense was appreciated enough to support such efforts, and not only muskets but also pistols and more difficult, artillery.

parts
Click to expand...
 
The major custom barrel makers have people that just cut the blanks to length, centerdrill each, drilled on the rifling machine, moved to be reamed, and now they will lap them in the better shops. It is now off to the rifling machine. I think Shilen has 3-4 dual spindle Pratt&Whitney deep hole drills. After rifling they are put in a vacuum heat unit for stress relieving and then the final lap.They will run a large lot of each bore size at a time. Shilen's button rifler was made by Ed Shilen .
 
The US manufacturers of P14/M17 rifles used broaching to rifle the barrels in one pass.Production started around June 1916 on the british contract,continued after early 1917 on US contract.Total production including modification period was somethig like 4 million of both types from mid 1916 to Nov 1918,or early 1919 in the case of the Eddystone factory.And probably another million barrels as spares.
 
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